1. Field of the Invention
This invention relates to the field of electric power generation, in general. More specifically it concerns a so-called combined cycle power generating system which employs at least two electric power generators one driven by a gas turbine and the other by a steam turbine.
2. Description of the Prior Art
While the use of a so-called combined cycle system in connection with electric power generation is known, it has been discovered that with a system consisting of one gas turbine and steam turbine a problem arises when it is desired to maintain efficient operation of the system at loads other than full load, particularly at loads as low as 1/4 of full load. If the direct approach is to be employed of reducing the power level of both the gas turbine and the steam turbine of such combined cycle to 1/4 load, the result creates a gross mismatch between the gas turbine and the steam cycle because of the low exhaust temperatures of the gas turbine with little reduction in exhaust mass flow.
Consequently, it is an object of this invention to provide an improvement for a combined cycle electric power generation system which permits the operation at greatly reduced loads without loss of efficiency.
Another object of the invention is to provide for a system that incorporates combined cycle electric power generation with a fuel gas generation system. The latter produces fuel for the combustor of the combined cycle system, and the total combination incorporates the improvement according to this invention for obtaining efficient operation under low loads.